The present application claims priority to German Application No. DE 100 44 943.3, which was filed on Sep. 12, 2000 and German Application No. DE 101 32 947.4, which was filed on Jul. 6, 2001; the entire contents of both documents are incorporated herein by reference.
1. Field of the Invention
The invention provides nucleotide sequences from Coryneform bacteria which code for the RodA protein and a process for the fermentative preparation of amino acids using bacteria in which the rodA gene is enhanced.
2. Discussion of the Background
L-Amino acids, in particular L-lysine, are used in human medicine and in the pharmaceuticals industry, in the foodstuffs industry and, particularly, in animal nutrition.
It is known that amino acids are prepared by fermentation from strains of Coryneform bacteria, in particular Corynebacterium glutamicum. Because of their great importance, work is constantly being undertaken to improve amino acid preparation processes. Improvements to the process can relate to fermentation measures, such as, stirring and supply of oxygen; the composition of the nutrient media, such as, the sugar concentration during the fermentation; o working up to the product form with, for example, ion exchange chromatography,; or altering the intrinsic output properties of the microorganism itself.
Methods of mutagenesis, selection and mutant selection are used to improve the output properties of these microorganisms. Strains which are resistant to antimetabolites or are auxotrophic for metabolites of regulatory importance and produce amino acids are obtained in this manner.
Methods of the recombinant DNA technique have also been employed for some years for improving the strain of Corynebacterium strains which produce L-amino acids, by amplifying individual amino acid biosynthesis genes and investigating the effect on the amino acid production.
However, there remains a critical need for improved methods of producing L-amino acids and thus for the provision of strains of bacteria producing higher amounts of L-amino acids. On a commercial or industrial scale even small improvements in the yield of L-amino acids, or the efficiency of their production, are economically significant. Prior to the present invention, it was not recognized that attenuation of the rodA gene encoding the cell division protein RodA would improve L-amino acid yields.
An object of the present invention is to provide novel measures for the improved production of L-amino acids or amino acid, where these amino acids include L-asparagine, L-threonine, L-serine, L-glutamate, L-glycine, L-alanine, L-cysteine, L-valine, L-methionine, L-isoleucine, L-leucine, L-tyrosine, L-phenylalanine, L-histidine, L-lysine, L-tryptophan, L-arginine and the salts (monohydrochloride or sulfate) thereof.
One object of the present invention is providing a novel process for improving the fermentative production of said L-amino acids, particularly L-lysine. Such a process includes enhanced bacteria, preferably enhanced Coryneform bacteria, which express enhanced amounts of a RodA cell division protein or protein that has RodA protein activity.
Thus, another object of the present invention is providing such a bacterium, which expresses enhanced amounts of a RodA protein or gene products of the rodA gene.
Another object of the present invention is providing a bacterium, preferably a Coryneform bacterium, which expresses a polypeptide that has enhnaced RodA protein activity.
Another object of the invention is to provide a nucleotide sequence encoding a polypeptide having the RodA protein sequence. One embodiment of such a sequence is the nucleotide sequence of SEQ ID NO:1.
A further object of the invention is a method of making RodA protein or an isolated polypeptide having the activity of RodA, as well as use of such isolated polypeptides in the production of amino acids. One embodiment of such a polypeptide is the polypeptide having the amino acid sequence of SEQ ID NO:2.
Other objects of the invention include methods of detecting nucleic acid sequences homologous to SEQ ID NO:1, particularly nucleic acid sequences encoding polypeptides that have the activity of RodA, and methods of making nucleic acids encoding such polypeptides.
The above objects highlight certain aspects of the invention. Additional objects, aspects and embodiments of the invention are found in the following detailed description of the invention.